Thrush in a Newborn's Oral Cavity Becomes Less Frequent as the Infant

Thrush in a newborn's oral cavity becomes less frequent as the infant ages.What is the most likely reason for this?

A) The infant begins to produce antifungal antibodies.
B) The eruption of the teeth inhibits the growth of yeast.
C) The acquisition of normal microbiota prevents the overgrowth of yeast.
D) Vaccines given in early infancy prevent the development of thrush.